1. Field of the Invention
The invention relates to a flexible cable carrier which undergoes wear when it loops back and slides upon itself and special pads included to reduce associated galling and wear.
2. Discussion of the Related Art
Tape libraries are now quite popular for storing large amounts of data. Because of the largeness of some of these libraries, automation has been employed in the retrieval of information from the tapes or the addition of information thereto. A very efficient automated library now in use uses a remote control apparatus which has a traveling manipulative arm. The magnetic tape cartridges are located along a wall in rows and columns. The remote control apparatus is located on a trolley which rides on a track along the tape-filled wall. An automated host system transmits robotic power and control signals to the trolley and manipulative arm. The host system remotely controls the trolley and manipulative arm to retrieve a selected tape, place it in a tape reading and recording device, and then return it to the library when the desired function is completed. The same can be done with optical and magnetic disc cartridges or other media in lieu of tapes.
The power and control signals are fed to the trolley and manipulative arm via molded ribbon cabling, also known as Flagstaff cable. Ribbon cable is a group of cables which are positioned side by side in a molded flexible sheath. Elongated channel shaped carriers receive edge portions of the ribbon cable and ride in an elongated recess alongside the trolley track to confine the ribbon cable and prevent it from snarling with the rest of the retrieval apparatus. These carriers are normally constructed from plastic, such as polypropylene. One end of the carrier and ribbon cabling is connected to a fixed power and signal source while the other end is connected to the trolley and moves back and forth therewith. Because of this arrangement, the carriers loop back and slide upon themselves upon movement of the trolley. This sliding action takes place along an elongated surface formed inside the loop of the carrier.
Because of the high speed of the trolley and the considerable length of the library, a significant amount of friction occurs when these carriers slide upon themselves. This friction causes substantial wear of the plastic carrier and leads to galling. The galling produces frictional debris that requires a periodic cleanup in order to keep the library functional. The cleanup is tedious because of the many corners, crevices and cavities in the library. In an attempt to reduce wear and galling, the carrier material was changed from polypropylene to polyamide which is more expensive. While there was some reduction in the wear and galling it was not nearly sufficient. The library still became contaminated with debris that might affect recording operation.